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Free Energy · 30 August 05

In the mid 80’s I spent some time between jobs at my Mom’s cabin in Wyoming. I made a little solar cell tracker out of an old turntable, threw together a passive solar hot water heater, repaired an old water pump, and then tried to build a wind setup to drive it.

Mom lived then, and still does now, pretty simply. No running water (except the creek outside), no commercial power, and only a wood stove for heat. It’s a nice place. Quiet and beautiful and unencumbered.

Somewhere around that time I took a side trip to Casper, which is pretty much an all day trip from the cabin. At a store in town I saw the coolest thing: a spinning chrome kinetic sculpture. Give it a push and the planets rotate around and around on their rings forever.

Kinetic Gadget

Imagine the possibilities! I was motivated. Back at the cabin I dug out coat hangers and magnets and set to work making my own. The idea was to come up with the perfect balance of magnets on each of the rings. Once pushed into motion the magnets kept resisting (or attracting) each other as they passed, never able to fully stop.

If you’ve ever tried making something precise with coat hangers you can probably understand that this wasn’t an easy project. Bend, tweak, spin, and start all over. The ring would spin for a while but eventually run down. A little more tweaking and it would run a while longer. Tweak, tweak, tweak…

Working with coat hanger sculptures is one thing, trying to create perpetual motion is a whole other can of worms. What I’d missed with the spinning gadget at the mall was a hidden electro-magnet in the base powered by a 9 volt battery. That is what kept things spinning.

We all have our lapses. Once a month I get an email from a well meaning person suggesting how to get more range and it only involves bending the laws of physics a little.

When our EV was first completed I was showing it to the guys at the office and someone wandered by. “You gonna put a wind generator on it to charge the batteries while you drive?”

Wind Gen on Truck

The guys over at OtherPower have the market sewed up in wind gens on trucks (pictured), but they only do it to test the generator…no perpetual motion involved. Great group with great mottos: “The blunt edge of High Tech” and “More time than money.” Be sure to check out their latest handmade wind generator.

Actually I don’t get many emails suggesting a wind generator. Usually the idea is to take some small generators or magnetos or alternators and hook them to the wheels or drive shaft. Not for brake regeneration (slowing down with the alternator and feeding excess into batteries) but having them hooked up all of the time.

“But that’s perpetual energy.” I respond.

No, they are small generators, you’d be grabbing just a little bit of power,“ they reply.

“Generators put a load on the car, the EV motor has to work harder to spin it, in the end you lose more power.” I trump.

No, no, really small generators…

Which reminds me of another story. Around the same time that I was inventing a perpetual motion coat hanger I decided to make a human powered generator for Mom. Her solar panel at the time was very small and I figured it would be easy enough to make a pedal powered generator to charge the battery.


An old bicycle was mounted to a metal stand welded out of spare parts. Also welded onto the stand was a mounting point for the alternator. Next came a field trip to the local salvage yard. I wanted to make TONS of power so I picked the biggest alternator I could find.

The alternator was hooked via a big fan belt wrapped around the rear wheel. Cables hooked it to the house batteries via a switch on the handlebars. The idea was to get everything spun up to speed and close the switch: house lights grow bright, and batteries start gurgling under the charge.

The problem was that I hadn’t come up with a way to limit the charge and thereby limit the load. Turn on the switch and it was like applying disc brakes…it would shoot Mom off the bike and across the room!

Being of the Wiley Coyote school of engineering I knew the answer: more mass. Off came the back wheel, clamped into a mold, and filled with cement. It took a while to pedal it up to speed but when you hit the power switch it didn’t come to an immediate stop.

Mom's Cabin

Of course it took Mom a couple of minutes to get it up to speed and once the switch was on she could barely last for another minute. Heck, I biked every day and could barely keep it spinning for more than five minutes.

The moral of the story is that you always have to give something to get something, at least with energy. Even without the alternator it was quite a task to spin things: more mass was going around, more moving parts, friction losses, you name it.

The problem with most of these proposals I get is that it involves adding things to the car. When you add an item to the car you immediately increase the amount of work needed to move the car…even if YOU can’t feel the difference or don’t have instruments sensitive enough to measure them.

First there is the added weight. A Hummer gets much less gas mileage than a Camry in part because it weighs 6400lbs vs. 3108lbs.

As you probably suspected, the guy with the really large tires on his truck is getting much less gas mileage than the fellow with stock tires. “There is this rule of thumb among racers that adding weight to something that rotates is far more detrimental to performance than if you add it to the body of the car.” Sport Compact Car Mag A four wheel drive, or even a vehicle with a longer drive shaft, is putting more of this undesirable rotational mass on the motor.

That’s not to say that there aren’t any ways to get free energy. Free being a matter of interpretation, some might call it not wasting existing energy in the first place.

You’ve heard it a million times and here it is again: if your vehicle’s tire pressure is low you are wasting energy. Maybe lots of it. Go let half of the air out of your bike tires and try to pedal around town for an hour, you’ll get the idea. Some EVs go so far as to use low rolling resistance tires. Low rolling resistance is a fancy way of saying less traction, but traction comes from friction and it is a trade-off between getting enough traction to be safe and keeping it low to save on unnecessary friction.

Prius vs. Escalade

Then there’s aero-dynamics, or lack thereof. Reducing the vehicle drag is tougher for you and I converting an existing vehicle. Best bet is to start off with a donor vehicle that already has low wind resistance.

The Hummer, at 0.57, is somewhat sleeker than a moving brick wall. The Camry has a drag coefficient of 0.28. Those funny looking Honda Insights with the enclosed back wheels have a drag coefficient of 0.25 while a Prius is at 0.26. For comparison a VW Beetle is 0.38. Drag has more effect the higher the speed you drive, so an EV tooling around town at twenty miles an hour won’t benefit from drag reduction as much as a Montana driver doing 90mph down the interstate.

To reduce drag a pickup can lower keep the tailgate up)#Tailgate_Up_vs._Tailgate_Down or mount a lightweight bed cover to cut back on wind resistance. Get rid of the antenna doo-hickeys and flapping american flags, roll up the windows, even washing the car helps. All depends on how picky you want to get.

If you own an EV there are other ways to cut back on energy use. Use the largest guage wire that you can, both in the car and for charging it. Wire has resistance and the larger the wire the lower the resistance. Resistance being what it sounds like: something that “resists” electrical energy moving.

An extension cord is a good example. Maybe you bought a fifty footer just in case you need to charge from a distant socket. Shorter cords with heavier gauge (gauge numbers get smaller as the wire gets bigger) have lower resistance, which saves energy and makes for a safer system. Running too much current through small, long wires, be it an extension cord to the EV or to a space heater, causes the wire to overheat and even causes fires.

Wiring Parts

You also want solid connections: a bad connection means higher resistance. Sure, it’s only an ohm or some fraction of one, but when the motor starts pulling 300 amps that little bit of resistance turns into a heating element. I’ve read more than a few EV conversions where standard car battery clamp-on terminals were used and melted down under load.

The biggest energy saving step you can make with an EV is identical to the ones you make with a gas vehicle: pick the right car for the job. Making your vehicle electric doesn’t impart a magical ambiance that suspends the laws of physics. If it’s a large, gas guzzling vehicle it will be a large, electricity guzzling vehicle after conversion.

Finally a word about Solar panels. Next to magnetos on the wheels, solar panels on the roof has to be the next most popular suggestion. I think it’s a good and a bad idea, let me tell you why.

Most solar panels consist of a bunch of solar cells wired in series. Series means that they are chained together like beads on a bracelet: if one breaks, they all fall down. Same thing happens with shade: if one gets less light, it impedes the power output of the whole panel. Newer panels are being designed to work around this but it’s not prevalent or perfect.

Solar panels also have an angle of effectiveness. The more of angle that the sun is off, the less power. That’s why some solar arrays have trackers, to help follow the sun across the sky and maximize the power extracted.

“So what,” you say, “Every little bit helps!”

The problem is that the solar panels add weight to the vehicle and, unless you are pretty handy, they also add drag. A typical commute isn’t very long and any power gathered by the panels is miniscule compared to what is needed to power the motor. The panels are also pretty expensive, which is a pity to waste on a roof top mount that weighs the car down and provides little benefit.

Still, solar panels themselves aren’t a bad idea.

Spend your time and money to mount the solar panels in a well lit spot that will generate power throughout the day. Sell it back to the electric company, using them as your storage system. Or maybe your employer will let you mount panels in the office parking lot to help re-charge the EV during the work day.

If you install solar in the next two years you might qualify for a $4k deduction.

Comments 15
  1. — Dan    Apr 03, 2006 13:39 PM    #

    Great post, it gave me flashbacks.

    First, I did that “bicycle to junkyard alternator” project in college. We had to use alternate energy to cook an egg. I used a small alternator and a 10-speed bike. I found that if I was riding furiously in 10th gear, I was able to heat a small home-made oven and put a tiny bit back into the battery.

    Secondly, I’ve had people ask why nobody has made an EV with a motor on one wheel and an alternator on each of the other three wheels: “that way it would produce more energy than it uses.” ;^)

  2. — caleb    Jan 30, 2007 22:46 PM    #

    myth busters had a show that proved that putting the tailgate down actually increases drag.

  3. jerry Halstead    Jan 30, 2007 23:23 PM    #

    You’re right. I saw that (and read another lab’s report saying the same thing), and totally forgot to update the entry. Thanks, Caleb!

    p.s. didn’t they do a follow-up and find that a lightweight tailgate net worked even better?

  4. — jesse    Jun 02, 2007 15:28 PM    #

    I’ve bin considering a conversion. My plans are only abstract so far but I was wondering if, in general you could get more of a benefit from putting a wind plant generator in the air intake or sealing it up to improve aerodynamics?

  5. — jesse    Jun 02, 2007 16:31 PM    #

    I see a lot of people talking about converting pickups and suvs. Wouldn’t a van (epically a minivan) be a far more aerodynamic choice for a large interior vehicle?

  6. — Robert    Aug 15, 2008 08:14 AM    #

    I’ve been pondering the same ideas here for some time. I think a van would be great. Here’s my thoughts…(give me feed back) You get a van front wheel drive convert it… obtain a rear wheel drive axle that will fit. Install it facing the rear. Gear up through the floor. Run it to several alternators. Once you get the van to a certain speed you can take over power, no? Or have a double set of batteries to be able to switch off. Also have solar on the roof for trickle power charge the batteries. I’ve been saying “in-wheel motors” for years and now we’re seeing them. don’t worry they’re going to suck us dry with this gas b.s. then they’ll introduce us to electric and continue to make ridiculous profits. Stop listening to the media and big oil telling us lies about it being too hard and out of reach. My high school science teacher told me you couldn’t run a car on Hydrogen…. Now alot of people are doing it.
    I don’t expect my idea is “free energy” or “perpetual motion” I do think that if we can reduce the charging time and the energy loss by simpler thinking and not making things so complex that we’ll be set… Now I just have to come up with $6,000.00 so I can convert my van.

  7. Jerry    Aug 15, 2008 08:22 AM    #

    Yes, your idea is perpetual energy and no, you don’t have to spend $6,000 before you can discover this. Go buy a little remote controlled car that runs off of batteries and try your experiment. Add a fifth wheel or some other means to drive a small generator and then get back to us when you have it powering the car further than the car would normally go on batteries alone.

  8. — Dan P.    Aug 15, 2008 14:46 PM    #

    I just took my father and son to breakfast and had basically the same discussion with dad.
    His idea was to install a stator set up like a motorcycle has to the front side of a double shafted motor which would then charge the batteries or at least the cars auxiliary one for headlights etcetera while you were driving down the road.

    Here is a link for the type of item I’m talking about. http://www.hotbikeweb.com/tech/0608_hbkp_compu_fire_charging_system/index.html

  9. — Patrick D.    Aug 24, 2008 15:44 PM    #

    Since the “Magna-Charger” is an induction-based charger (the paddles), would it be possible to create an induction based charger that’s in the car itself?

    Even if it took the place of the DC-DC charger that you currently have, it would improve the range somewhat (even if it’s miniscule).


  10. — dustin    Dec 31, 2008 19:30 PM    #

    I live in texas and my car spends a great great deal of my work day sitting static in the parking lot. It seems like a lot of charging would be able to take place in the six or seven hours of direct sunlight that my car is exposed to everyday. Obviously you would not want to simply slap a solar panel onto your car and call it a day, but if the system is designed in a smart way it seems that it would increase the range of a vehicle that is used to primarily as transportation to and from work. My scenario is not everyones but there sure are alot of cars here in fort worth that could be helping to provide fuel for their owners if this were a correct thought. There are solar films out now that weigh less and can conform to the shape of the roof etc. Expensive yes, but coming from a green standpoint profit is not always measured in dollar signs. At the very least, it seems a small solar setup could be used to power the accesories while in use and could provide low amp charge to keep the batteries excited while sitting.

  11. Jerry    Dec 31, 2008 19:53 PM    #

    I’d say your best bet is to put the panels on a permanent mount in the parking lot. You aren’t carrying around the weight of them all of the time and can optimize the mounting angle for the time of the season.

  12. — EVdude    Jan 01, 2009 13:27 PM    #

    Jerry, you didn’t read the whole post CAREFULLY. he said that he was considering buying solar film not panels. there are other solar materials besides panels which are just as efficient but several times lighter. the only drawback is that they are expensive. very very very expensive. but the more you buy the less it costs per watt. i have never seen any for vehicles but i have seen some made of roofing material. the cheapest roofing material i have seen costs $1.35 US dollars per watt but in order to get that price you have to buy $60,000 US dollars worth of material. i am sure someone has adapted a similar material for vehicles. but the drawback is one you pointed out above. it would be hard and expensive to mount it at an optimal angle to capture sunlight.

  13. Jerry    Jan 01, 2009 16:17 PM    #

    I understood what he wrote, but still feel the static mounted ground collector is a better way. Film still needs to be mounted, protected, and wired along with any associated control electronics. That adds weight and complexity even with film.

    Hey, maybe it folds up into a little aerodynamic trailer that then opens like a flower when you are parked and tracks the sun! “:^)

  14. — EVdude    Jan 01, 2009 20:29 PM    #

    i agree with that it would be really complex. and i also agree that it would probably be better to mount the panels at work.

  15. — jjackstone    Jan 02, 2009 15:34 PM    #

    Also the thin film solar still has lower efficiencies. You’d need, in general, two to three times the amount of material as a crystalline structure.